1215
J. Am. Chem. SOC.1993,115, 7275-7284
Facile Haptotropic Shifts in Organometallic Complexes of 4H-Cyclopent a [de8 phenant hrene via Napht halene-Type Transition States: Synthetic, X-ray Crystallographic, NMR Spectroscopic, and EHMO Studies Andreas Decken, James F. Britten, and Michael J. McClinchey' Contribution from the Department of Chemistry, McMaster University, Hamilton, Ontario U S 4M1, Canada Received November 16, 1992
Abstract: The tetracyclic system 4H-~yclopenta[def]phenanthrene(cppH) forms the complexes (q6-cppH)Cr(CO)3 (2)
and [(q5-cppH)Mn(C0)3]PF6(13); in both cases the metal is bonded to a terminal ring. Molecule 2 crystallizes in the orthorhombicspace group Pbca, with a = 13.924(2) A, b = 12.639(2) A, c = 15.666(3) A, and Z = 8. Deprotonation of 2 and 13 a t room temperature yields [(qs-cpp)Cr(C0)3]- (7) and (q5-cpp)Mn(CO)3 (15), respectively, with no detectable zwitterionic intermediate. 15 crystallizes in the monoclinic space group P2l/c, with a = 11.274(2) A, b = 8.752(2) A, c = 14.404(3) A, 6 = 98.64(3)O, and Z = 4. The corresponding 8,9-dihydro-cpp derivatives (76-H~cppH)Cr(C0)3 (24) and [ ( T J ~ - H ~ - c ~ ~ H ) M ~ ( C(17) O ) have ~ ] P also F ~ been prepared. 24 crystallizes in the orthorhombic space group Pbca, with a = 12.662(3) A, b = 14.594(3) A, c = 15.761(3), and Z = 8. Upon deprotonation, 17 yields an intermediate neutral complex (18) which undergoes an q6-to-q5-haptotropic shift only upon being heated to 60 OC for 1 h. The whole process can be followed readily by NMR. The corresponding neutral intermediate derived by deprotonation of 13 can be trapped at -40 O C . The relative ease of haptotropic shifts in the cpp complexes relative to the analogous H2-cpp systems can be rationalized in terms of a transition state in which the migrating organometallic fragment is $-bonded to the polycyclic ligand such that a 1 0 (naphthalene-like) ~ character is retained.
Introduction
The molecule 4H-~yclopenta[deflphenanthrene(cppH) (1) not only contains the carbon skeletons of indene, acenaphthylene, phenanthrene, and fluorene (see Figure l), but, as shown in Figure 2, it also represents 25% of the Cg, framework. It is an attractive ligand because it offers multiple sites for the attachment of organometallic moieties which can potentially bind in an q6-,q5-, 74-, 93-, 32-, or 71-fashion. To our knowledge, no transition-metal complexes of this ligand have been reported. Moreover, deprotonation of @-complexes of the cppH ligand provides the opportunity for haptotropic shifts by ML,units from (or through) six-membered rings to a five-membered ring. Such inter-ring migrations have been the subject of considerable theoretical analysis, notably by Albright, Hoffmann, and their colleagues.' These calculated barriers compare very favorably with the reported experimental data.2 In particular, it has been shown that the ability of organometallic fragments to migrate across the surfaces of polycyclic systems can be rationalized in terms of the interactions between the frontier orbitals of the ML, moiety and of the T system. For example, the metallotropic shift of a (CsH5)Fe unit in the indenyl anion, shown in Figure 3a, is calculated to proceed not via a least-motion pathway from ring center to ring center (route A) but rather via an exocyclic q3transition state (B).I In contrast, EHMO calculations on the [(pentalene)Fe(CsHs]+ system, shown in Figure 3b, suggest that a (CsH5)Fe moiety can move across the common bond between the two rings; however, even in this case, the trajectory does not follow the least-motion pathway.' Of particular significance here is the fact that the *-electron count in the 4H-~yclopenta[deflphenanthrenesystem can be conveniently reduced by 2 merely by hydrogenating the C(8)=C (9) double bond. Thus one can make direct comparisons between (1) Albright, T. A.; Hofmann, P.; Hoffmann, R.; Lillya, C. P.; Dobosh,
P.A. J . Am. Chem. SOC.1983, 105, 3396.
(2) Rerek, M. E.; Basolo, F. Organometallics 1984, 3, 647.
9
8
4
i Figure 1. Polycyclic fragments contained in the cppH skeleton, also showing the numbering system.
polycyclic molecules possessing the same skeletal geometry but having different frontier orbital patterns. Results and Discussion Synthetic Aspects. The reaction of 4H-cyclopenta[deflphenanthrene (cppH) (1) with chromium hexacarbonyl yields the complex (q6-cppH)Cr(C0)3 (2), in which the tripodal fragment is attached to a terminal six-membered ring. Formation of this isomer parallels the behavior of other polyaromatic complexes, such as (phenanthrene)Cr(CO)3 (3), (anthracene)Cr(CO)3 (4), or (triphenylene)Cr(CO)1 (5); in all these cases, the metal binds preferentially to an outer ring of the polycyclic
0002-786319311515-7275$04.00/00 1993 American Chemical Society
1276 J. Am. Chem. SOC.,Vol. 115, No. 16, 1993
Decken et al. 4.6
P
4.4
Figure 2. Diagram of the cpp unit as a fragment of Cm. b)
a)
3.61 3.4h
Figure 3. (a) Metallotropic shift pathways in indenyl-metal complexes. (b) Favored pathway for a metallotropic shift in the pentalene system. 0 C
I
b d a
&
OC
CO
0:l
0:2
0:3 d.4 0.5 0:s 0:7 Mole fraction of benzene
d.8
d.9
Figure 4. Use of the ASIS effect to distinguish ex0 and endo methylenes in (tf-cppH)Cr(CO)j (2).
arene rings. Moreover, the appearance of the C(4) and Cr(C0)3 resonances at 6 60.4 and 245.8, respectively, provide compelling evidence for an $-complex. Our studies on the anionic species 7 were restricted to spectroscopic investigations in solution; however, we anticipated that use of cationic 76-precursors should yield neutral complexes which might be more readily amenable to X-ray diffraction techniques. A
@
I -Cr(CO),
6
7
system.3 This has been explained either by attributing greater aromatic character to a terminal ringdor, alternatively, by noting that in each case the observed isomer leaves conjugated the maximum number of noncomplexed rings.5 Although the assignments of the 13C and 'H N M R resonances of 2 were made by standard one- and two-dimensional techniques, the attribution of the ex0 and endo methylene protons at C(4) was not so trivial. This was achieved by taking advantage of the anisotropic solventinduced shift (ASIS) effect.6 As depicted in Figure 4, successive addition of aliquots of benzene to a CD2C12 solution of 2 led to a greater increase in shielding of one of the aforementioned methylene protons. It is the ex0 hydrogen which is the more exposed to the anisotropic solvent and so the attributions are evident. As expected from the published data for the analogous fluorene complex,' deprotonation of ($-cppH)Cr(C0)3 (2) yields a complex whose N M R spectra reveal that the Cr(C0)j fragment has migrated onto the cyclopentadienyl ring. The N M R spectra are consistent only with a molecule (7) possessing a single mirror plane, and the aromatic resonances are typical for noncomplexed (3) (a) Muir, K.W.; Ferguson, G.; Sim, G. A. J . Chem. SOC.B 1968,467. (b) Hanic, F.; Mills, 0. S . J. Organomet. Chem. 1968, 11, 151. (c) Rogers, R. D.; Atwood, J. L.; Albright, T. A,; Lee, W. A.; Rausch, M. D. Organomerallics 1984, 3, 263. (4) Elschenbroich, Ch.; Salzer, A. Organometallics--A Concise Inrroduction, 2nd ed.; VCH Publishers: Weinheim, Germany, 1989; p 345. (5) Fischer, E. 0.;Kriebitzsch, N.; Fischer, R. D. Chem. Ber. 1959, 92, 3214. (6) (a) Laszlo, P. Prog. N M R Specfrosc. 1967,3,231 . (b) Ustynyuk, N. A.; Novikova, L. N.; Bel'skii, V. K.; Oprunenko, Yu. F.; Malyugina, S. G.; Trifonova, 0. I.; Ustynyuk, Yu. A. J . Organomel. Chem. 1985, 294, 31. (7) Nicholas, K. M.; Kerber, R. C.;Stiefel, E. I. Inorg. Chem. 1971, 10, 1519.
Q9 I fM
+M
1 Oa
8 : M = [Mn(CO).J
9 : M = [Fe(C,H,)] M 10b
In his pioneering studies on fluorenyl complexes, Treichel showed that deprotonation of the cationic complexes 8 and 9 bearing such $-bonded fragments as Mn(CO)3+ or (CsH,)Fe+ yields isolable intermediates in which the metal remains attached to the six-membered ring.8 These neutral intermediates have been represented either as zwitterions, as in loa, or as molecules possessing a formal C(9)=C( 10) double bond, as in lob. X-ray diffraction studies on (fluorene)Fe(CsHs) and (fluorene)Mn(CO)3 revealed that the ligand is apparently bonded in a pentahapto fashion.gJ0 In the manganese case, the reaction continues whereby the Mn(CO)3 moiety eventually moves into the five-membered ring, 11. In the (cyclopentadieny1)iron analogue, Treichel was unable to detect ($-fluorenyl)($cyclopentadieny1)iron (12), but Ustynyuk et al. have claimed (8) (a) Treichel, P. M.; Johnson, J. W. Inorg. Chem. 1977, 16, 749. (b) Johnson, J. W.; Treichel, P. M. J . Am. Chem. Soc. 1977, 99, 1427. (9) Johnson, J. W.; Triechel, P. M. J. Chem. SOC.,Chem. Commun. 1976, 688. (10) Treicbel, P. M.; Fivizzanai,K. P.; Haller, K. J. Organomerallics 1982, 1, 931.
J. Am. Chem.SOC., Vo1. 115, No.16, 1993 7211
Haptotropic Shiftsin Metal-Cyclopenta[deflphenanthrene
manganese;l5 presumably, the reaction proceeds via the initially formed +-species 20, but this was not isolable. In contrast, the analogous reaction with iodo(pentacarbony1)rhenium yields the mono- and pentahapto complexes 21 and 22, respectively.'*
-
M 11 : M = Mn(CO),
A
12 : M = Fe(C,H,)
that this ferrocene analogue is produced.ll We are currently investigating the possible formation of (q5-cpp)Fe(v5-C5H5)and have already crystallographically characterized [ ($-cppH)Fe(q5-CsH5)]+PF6-.12 In contrast to the synthesis of the cation [(@-phenanthrene)Fe(CsH5)1+,which is always accompanied by much hydrogenation of the C(8)=C(9) double bond,'3 this is not a particular problem with [ (~f-cppH)Fe(q~-C~Hs)]+PF6-. The reaction of cppH with bromo(pentacarbony1)manganese in the presence of AlC13 yields the cationic manganese complex [($-cppH)Mn(CO)3]+PF6- (13). Unlike the situation with [ ($-cppH)Fe(+CsH5)]+PF6-, where hydrogen abstraction is not problematical, 13 is seriously contaminated with [ ($-HzcppH)Mn(CO)3]+PF6- (17) unless the solvent is very carefully dried. Interestingly, Nesmeyanov has noted that the use of very dry AlC13 in the preparation of [(arene)Fe(C~Hs)]+complexes leads to extremely poor yields; apparently, traces of water are necessary for the reaction to proceed sati~factori1y.I~
Deprotonation of the manganese cation [($-cppH)Mn(CO),]+PF6- (13) a t room temperature leads to (~5-cpp)Mn(CO)3 (15) with no detectable intermediacy of 14. However, generation of 14 can be accomplished readily at -40 O C by treatment of a dichloromethane solution of 13 with 1,8-bis(dimethy1amino)naphthalene (Proton Sponge, Aldrich). Rearrangement to the $-isomer 15 is evident at temperatures above 15 OC. In contrast, prior reduction of the C(8)=C(9) double bond of cppH to give H2-cppH (16), followed by complexation with Mn(CO)s+, yields 17. Subsequent deprotonation of 17 results in metal migration, but this process clearly occurs in a stepwise manner. Indeed, 18 is stable at room temperature in acetone solution for at least 24 h or in the solid state for several weeks at -20 OC. However, upon heating a hexane solution of 18 for 1 h, it is slowly transformed into the centrally-bonded isomer 19. This result mirrorsthe behavior of the (fluorenyl)Mn(C0)3 system 8 originally studied by Treichel.8 The IH N M R spectra of 17, 18, and 19 are shown in Figure 5. The pentahapto complex ( $ - ~ p p ) M n ( C 0 ) ~(15) can be independently synthesized in surprisingly good yield via the reaction of the cpp anion ClsH9- with bromo(pentacarbony1)(1 1) Ustynyuk, N . A.; Pomazanova, N. A,; Novikova, L. N.; Kravtsov, D. N.; Ustynyuk, Yu. A. Izv. Akad. Nauk SSSR,Ser. Khim. 1986, 7, 1688. (12) Decken, A.; Britten, J. F.; McGlinchey, M. J., manuscript in preparation. (13) Lee, C. C.; Demchuk, K. J.; Pannekoek, W. J.; Sutherland, R. G. J . Organomet. Chem. 1978, 162, 253. (14) Nesmeyanov, A. N.; Vol'kenau, N . A.; Bolesova, I. N.; Polkovnikova, L. S. Koord. Khim. 1975, 1, 1252.
20 : M = Mn
15 M = Mn
21 : M = Re
22 : M = Re
X-ray Crystallography. The structure of ($-cppH)Cr(CO), (2) was readily deduced from its IH and I3CN M R spectra, but
the establishment of the orientation of the tripodal substituent required an X-ray crystallographic determination. The preferred orientation of the tripod has been calculated in (phenanthrene)Cr(C0)3 (3), and X-ray data are in accord with this predi~tion.~c Our EHMOcalculations on (@-cppH)Cr(CO)s (2) indicate that it should mirror the behavior of 3. Indeed, as shown in Figure 6 , the molecular orbital pattern of cppH itself closely resembles that for phenanthrene; in contrast, the frontier orbitals of ClsHg-, i.e., the cpp anion, match those of the fluorenide anion in that the HOMO has a large pz coefficient at the C(4) position. The X-ray crystallographically determined structure of 2 appears as Figure 7 and reveals that the tricarbonylchromium tripod adopts the EHMO-predicted orientation. Numbers related to data collection are in Table I, and atomic coordinates and bond lengths are listed in Tables I1 and 111. It is noteworthy that the tetracyclic ring system in 2 is not planar but instead bends in a gentle arc away from the organometallic fragment. Such a tendency to fold away from the n-bonded ML, group has been noted previously in such polycyclic molecules as the a-and 8 0 (CO)3 complexes of methyl O-methylpodocarpate16 and also for the Cr(C0)zCS and (C~H5)Ruderivativesofestradiolor estrone.'' The free ligand cppH, 1, crystallizes in thin plates unsuitable for an X-ray structural determination, so the extent of deviation from planarity is unknown; of course, it was established many years ago that corannulene ( 6 ) is distinctly bowl-shaped.18 However, in corannulene each edge of the central five-membered ring is also part of a six-membered ring. In contrast, in cppH only three of these pentagonal sides are shared with peripheral six-membered rings. The molecule (v5-cpp)Mn(C0)3 (15) poses several interesting structural questions. One might wonder whether the metal binds in a genuinely pentahapto fashion, or does it perhaps have a tendency toward trihapto bonding, as has been found for (indeny1)Rh(C2H& and related systems?lg Moreover, the recently published structure of bis(fluoreny1)barium tetrakis(ammonia) reveals that the metal is considerably displaced from the ring (15) The isolated yields of 40%for (+cpp)Mn(CO), may be compared to thoseof (qS-C5H5)Mn(CO),(56%) and ($-CI,H9)Mn(CO), (1 1%): King, R. B.; Efraty, A. J . Organomet. Chem. 1970, 23, 527. (16) (a) Cambie, R. C.; Clark, G. R.; Gourdie, A. C.; Rutledge, P. S.; Woodgate, P. D. J . Organomet. Chem. 1985,297, 177. (b) Mailvaganam, B.; Perrier, R. E.; Sayer, B. G.;McCarry, B. E.; Bell, R. A.; McGlinchey, M. J. J. Organomet. Chem. 1988, 354, 325. (17) (a) Vessibres, A,; Top, S.; Ismail, A. A,; Butler, I. S.; Louer, M.; Jaouen, G.Biochemisrry 1988, 27, 6659. (b) Moriarty, R. M.; Ku, Y.-Y.; Gill, U. S.; Gilardi, R.; Perrier, R. E.; McGlinchey, M. J. Organometallics 1989, 8, 960. (18) (a) Hanson, J. C.; Nordman, C. E. Acta Crystallogr. 1976, 832, 1147. (b) Scott, L. T.; Hashemi, M. M.; Bratcher,M. S. J . Am. Chem. SOC. 1992,114,1920. (c) Borchardt, A.; Fuchicello, A,; Kilway, K. V.; Baldridge, K. K.; Siegel, J. S. J . Am. Chem. SOC.1992, 114, 1921. (19) (a) Mlekuz, M.;Bougeard,P.;Sayer,B.G.;McGlinchey,M. J.;Rodger,
C. A.; Churchill, M. R.; Ziller, J. W.; Kang, S.-K.; Albright, T. A. Organometallics 1986,5,1656. (b) Westcott, S. A.; Kakkar, A. K.;Stringer, G.; Taylor, N . J.; Marder, T. B. J . Organomet. Chem. 1990, 394, 777. (c) Merola, J. S.; Kacmarcik, R. T.;Van Engen, D. J . Am. Chem.SOC.1986,108, 329.
7218 J . Am. Chem. SOC.,Vol. 115, No. 16, 1993
Decken et al.
A
I 0
A
0
S.0
1 0
5.0
m
1-0
4 0
A A
kL - - ,
1 0
.
6 0
0
0
.
¶ O
n.w
. O
7 0
Figure 5. 'HNMR spectra of the (dihydro-cpp)manganese17, 18, and 19.
centers.*O Extended Huckel molecular orbital calculations on 15 tell us not only that the metal fragment should be situated a t a position displaced -0.1 A from the center of the five-membered ring toward C(4) but also that the tripod is preferentially oriented such that a carbonyl ligand is trans to the (24) carbon. This situation arises as a result of the very considerable localization (20) MBsges, G.; Hampel, F.; Schleyer, P.v.R.Organometallics 1992,II, 1769.
of the HOMO of the cpp- anion at C(4) (see Figure 6). Analogously, in ($-fluorenyl)Cr(CO)2NO (23)the chromium is displaced slightly toward the unique ring carbon; furthermore, it is the nitrosyl ligand which is found trans to the C H unit of the five-membered ring thus aligning the most strongly donating site with the best r-acceptor ligand.21 Although there is a preferred Orientation Of the Mn(C0)3 tripod Of l5 in the state, the barrier to tripodal rotation is too low to be measurable
Haptotropic Shifts in Metal-Cyclopenta [deflphenanthrene
-9-
J . Am. Chem. SOC.,Vol. 115, No. 16, 1993 1219
-
t
> a -
-11
-
Figure 6. Frontier orbital patterns for phenanthrene, cppH, cpp-, and for fluorenide; the HOMO in each case is marked with an asterisk.
Figure 7. View of (?6-cppH)Cr(CO)3(2) showing the atom numbering. Thermal parameters at 30% probability. For clarity, hydrogen atoms have arbitrary temperature factors.
in solution by N M R spectroscopy. Indeed, the Mn(C0)3 moiety still exhibits a very sharp W O singlet at -100 OC on a 500-MHz spectrometer. The factors controlling slowed tripodal rotation have been extensively explored in recent years.22 Crystals of ($-cpp)Mn(C0)3 (15) were grown from 1,2dichloroethane/heptane by using solvent diffusion techniques, and the structure was determined by X-ray crystallography. Atomic coordinates and bond lengths are listed in Tables IV and (21)Atwood, J. L.; Shakir, R.; Mailto, J. T.; Herberhold, M.; Kremnitz, W.; Bernhagen, W. P.; Alt, H. G. J . Organomet. Chem. 1979, 165,65.
V. In accord with the N M R data, the Mn(C0)3 moiety is indeed bonded to the five-membered ring, as shown in Figure 8. However, the metal is not attached centrally but rather is displaced toward the C(4) position such that the manganese-ring carbon distances are found tobeMn-C(4) 2.121(2) A, Mn-C(3a/Sa) 2.204(2) A, Mn-C( 10/ 11) 2.206(2) A. These findings corroborate the EHMO predictions. A further noteworthy structural result is the fact that the three six-membered rings attached to the cyclopentadienyl moiety are slightly folded away from the Mn(CO) 3 tripod. We have commented already on the molecular geometry of ($-cppH)Cr(CO)3 (2), and it should be compared with the molecular and crystal structure of the analogous 8,g-dihydro complex (q6-H2-cppH)Cr(C0)3(24), a view of which appears as Figure 9. Atomic coordinates and bond lengths are listed in Tables VI and VII. The most obvious point is that the ligand is no longer a flat molecule with a gentle arc but instead is markedly twisted. The C(8)-C(9) bond is no longer coplanar with the "fluorene-like" tricyclic unit but rather adopts a half-chair conformation such that the benzylic methylene unit bonded to the chromium-complexed ring is exo with respect to the metal (22) (a) McGlinchey, M. J. Adu. Organomet. Chem. 1992,34, 285. (b) Nambu, M.; Siegel, J. S. J . Am. Chem. Soc. 1988,110,3675. (c) Downton, P. A.; Mailvaganam, B.; Frampton, C. S.; Sayer, B. G.; McGlinchey, M. J. J . Am. Chem. SOC.1990, 11 2, 27. (d) Mailvaganam, B.; Frampton, C. S.;
Sayer,B.G.;Top,S.;McGlinchey,M.J.J.Am.Chem.Soc.1991,113,1177. (e) Nambu, M.; Hardcastle, K.; Baldridge, K. K.; Sicgel, J. S. J . Am. Chem. SOC.1992,114,369. ( f ) Kilway, K. V.; Siegel, J. S. J . Am. Chem. Soc. 1992, 114,255. (8) Kilway, K. V.;Siegel, J. S. Organometallics 1992, 11, 1426. (g) Downton, P. A.; Sayer, B. G.; McGlinchey, M. J. Organometallics 1992, 11, 3281.
1280 J. Am. Chem. Soc., Vol. 115, No. 16, 1993 Table I.
Decken
et
al.
Crystallographic Data for (q6-cppH)Cr(CO)3(2), (q6-H2-cppH)Cr(CO)3 (U), and (v5-cpp)Mn(CO), (IS) 2
empirical formula color habit crystal size, mm3 crystal system space group a, A
4A
c, A 8, deg
v.A3
Z. formula weight d(calc), Mg/m3 w, cm-1 diffractometer radiation
CI~HIOC~O~ orange-red square biprism 0.65 X 0.5 X 0.45 orthorhombic Pbca 13.924(2) 12.639(2) 15.666(3) 2757(1) 8 326.3 1.572 9.40
2913(1) 8 328.3 1.497 7.94
Siemens P4 Mo K a (A = 0.710 73 A) 300 graphite 3.5-50.0 28-8 3 stdl97 refln 0 I h I 15,O I k I 14-17 I I I 0 2493 2136 1642 (F I 2.047)) 0.433210.4690 scan
T.K monochromator 20 range, deg scan type std refln index ranges rflns collected indepdt rflns obsd rflns minlmax transm abs. corr.
x = 0.0019(7) wl
= $(F) + 0.0009*F
20 1 5.36 6.39 1.42 0.019 0.003 8.2 0.23 -0.25
2059(1) 1837(3) 1504(3) 795(3) 444(3) -3 15(3) -377(3) -927(3) -794(4) -1 54(4) 434(3) 11lO(3) 1599(3) 1441(3) 289(3) 761(3) 2743(3) 1932(3) 3193(3) 3168(2) 1853(2) 3911(3)
~
Siemens R3m/V Ag K a (A = 0.560 86 A) 300 graphite 7.0-45.0
W
W
3 stdl97 refln -1 Ih I 15,-1 Ik I 17-1 I I I 18 3240 2546 2012 (F I4.0u(F)) 0.579/0.615 scan
+
Solution and Refinement x = 0.000 45(8) wl = u2(F)+ 0.000 0 3 2 * F 20 1 5.94 6.46 4.01 3.638L 0.224c 10.0 0.50 -0.40
Table II. Atomic Coordinates (X104) for ($-cppH)Cr(CO), (2) X
ClsH9MnO3 red square biprism 0.35 X 0.4 X 0.45 monoclinic mllc 11.274(2) 8.752(2) 14.404(3) 98.64(3) 1405.1(7) 4 328.2 1.551 5.0
Data Collection Siemens P4 Mo Ka (A = 0.710 73 A) 300 graphite 7.0-45.0
+
extinction correction" weighting scheme no. parameters refined R,b '% Rw,C'% GOFd Alu (max) A/u (mean) NoINv AP-, e A-' Ap, e A-3
15
24
Crystal Data C I sH I 2CrO3 yellow parallelepiped 0.7 X 0.4 X 0.4 orthorhombic Pbca 12.662(3) 14.594(3) 15.761(3)
Y
Z
-26(1) -323(4) -1 183(4) -1093( 3) -90(3) 345(3) 1508(3) 2343(4) 3320(4) 3498(4) 2639(4) 2599(4) 1701(4) 708(3) 1696(3) 764(3) -1067(3) 618(3) 695(4) -1 7 12(3) 970(3) 1144(3)
1335(1) 049(3)412(3) 1082(3) 1259(2) 1870(3) 1622(3) 1867(3) 1464(3) 828(4) 536(3) -1 29(3) -346(3) 98(3 962(3) 747(2) 1879(3) 2376(3) 1165(3) 2236(2) 3058(2) 1076(2)
fragment. This has the effect of twisting the noncomplexed half of the molecule. We note that a preliminary report on the molecular structure of (9,1O-dihydrophenanthrene)Cr(CO)3 ap-
3 stdl97 refln
0 I h I 15,O I & I11,-19 I I I 19 3938 3764 2609 (F I 4.0u(F)) 0.72410.786 scan
+
N WL I A= u q F ) + O.O015*F 235 3.71 4.68 0.92 0.021 0.002 11.1 0.45 -0.25
Table III. Bond Length (A) for ($-cppH)Cr(CO)3 (2)
2.224(4) 2.252(4) 1.835(4) 1.381(7) 1.387(6) 1.523(6) 1.400(7) 1.405(7) 1.451(7) 1.152(6) 0
Cr-C(2) Cr-C(9A) Cr-C(22) C(l)-C(9A) C(3A)-C(4) C(SA)-C(S) C(6)-C(7) C(8A)-C(lO) C(9A)-C( 11) C(22)-0(2)
2.197(5) 2.314(4) 1.832(5) 1.428(7) 1.528(6) 1.360(7) 1.356(8) 1.381(6) 1.391(5) 1.162(6)
Cr-C(3) Cr-C(l1) Cr-C(23) C(Z)-C(3) C(3A)-C(11) C(SA)-C(lO) C(7)-C(8A) C(8)-C(9) C(lO)-C(ll) C(23)-0(3)
-
2.251(4) 2.26 l(4) 1.843(5) 1.446(6) 1.415(5) 1.408(6) 1.434(7) 1.366(7) 1.391(6) 1.158(6)
23
peared a number of years ago?3 and the nonplanarity of the tricyclic ligand was detected. It is also instructive to look a t the packing of the molecules in the unit cell. The molecules of 2 are arranged in a head-to-head (23) Muir, K. W.; Ferguson, G.; Sim, G. A. J. Am. Chem. Soc. B 1968, 476.
J . Am. Chem. SOC.,Vol. 115. No. 16, 1993 7281
Haptotropic Shifts in Metal-Cyclopenta[deflphenanthrene Table IV. Atomic Coordinates (X1@) for ($-cpp)Mn(CO)o (15) X
-2408(1) -93 l(3) 4(3) 163(2) -664(2) -870(2) -1 860(2) -2471(2) -3383(2) -3766(3) -3447(3) -3240(2) -2770( 3) -1766(6) -2306(2) -1 597(2) -3637(2) -1844(2) -3277(3) -4402(2) -1 454(2) -3836(2)
Y -2175(1) -4467 (3) -3458 (3) -2860(3) -3 283(3) -2968 (3) -3914(3) -4260(3) -5314(4) -6062(3) -6358 (3) -5754(3) -5970(3) 4920(3) -4669(3) 4284(3) -2211(3) -422(3) -1 176(4) -2249(3) 693(3) -552( 3)
z
-391(1) -231 l(2) -1953(2) -1056(2) -447(2) 510(2) 694(1) 1465(2) 1330(2) 474(2) -1259(2) -308(2) -1 922(2) -1754(2) -156(2) -843(1) -1347(2) -77 l(2) 358(2) -1962( 1) -1 0 16(2) 838(2)
Figure 9. View of (H2-q6-cppH)Cr(CO)3(24) showing the atom numbering. Thermal parameters at 30% probabilityafter correction for librational motion. For clarity, hydrogen atoms have arbitrary temperature factors. Table VI. Atomic Coordinates (X lo4) for ($-H*-cppH)Cr(CO)o (24) X
Cr Table V. Bond Length
(A) for ($-cpp)Mn(CO)a
Mn-C(3A) Mn-C(l0) Mn-C(22) C(l)-C(9A) C(3A)-C(4) C(SA)-C(S) C(6)-C(7) C(8)-C(9) C(9A)-C(Il) C(22)-0(2)
Mn-C(4) Mn-C(l1) Mn-C(23) C(2)-C(3) C(3A)-C(11) C(SA)-C(10) C(7)-C(8A) C(8A)-C(10) C(lO)-C(ll) C(23)-0(3)
2.205(2) 2.210(2) 1.778(3) 1.385(4) 1.458(3) 1.424(3) 1.405(4) 1.352(4) 1.410(3) 1.148(4)
2.121(2) 2.202(2) 1.790(3) 1.380(4) 1.421(3) 1.415(3) 1.376(4) 1.410(3) 1.404(3) 1.142(4)
C(1)
(15)
Mn-C(SA) Mn-C(21) C(l)-C(2) C(3)-C(3A) C(4)-C(4A) C(S)-C(6) C(8)-C(8A) C(9)-C(9A) C(21)-0(1)
2.204(2) 1.801(2) 1.412(4) 1.423(4) 1.447(3) 1.374(4) 1.454(4) 1.450(4) 1.140(3)
C(22) C(23)
552(1) 386(7) -569(7) -1038(4) -472(4) -700(6) 335(8) 708( 12) 1771(1 7) 2406( 12) 2020(6) 2655(5) 20 18(6) 985(4) 1025( 5 ) 527(3) 62(4) 933(5) 1837(4) -238(3) 1165(4) 2639(3)
Table W. Bond Length
Cr-C(1) Cr-C(3A) Cr-C(21) C(l)-C(2) C(3)-C(3A)
2
1291(1) 2382(3) 2184(5 ) 1375(5) 754(3) -161(4) -430(4) -ll69(5) -1 133(9) -473(9) 278(7) 1023(9) 1838(5) 1758(3) 260(4) 965(3) 1489(4) 205(4) 1631(3) 1631(3) -488(3) 1861(3)
(A) for (n6-H2-cppH)Cr(COh(24)
Cr-C(3) Cr-C(l1) Cr-C(23) C(2)-C(3) C(3A)C(11) C(4)-C(SA) 1.544(11) C(5A)-C(5) 1.371(11) C(5A)C(10) C(S)-C(6) 1.439(25) C(6)-C(7) 1.316(22) C(7)C(W C(8A)-C(8) 1.454(15) C(8A)1.339(10) C(8)-C(9) C(10) C(9)-C(9A) 1.501(9) C(9A)1.380(7) C(10)C(11) C(11) C(21)-0( 1) 1.152(6) C(22)-0(2) 1.150(7) C(23)-0(3)
Figure8. Views of ($-cpp)Mn(CO)a (15) showing the atom numbering. Thermal parameters at 30% probability. For clarity, hydrogen atoms have arbitrary temperature factors.
manner such that closest neighbors have their tetracyclic ligands aligned parallel to each other a t an interplane distance of 3.45 A. From a comparison of the crystal packing of ($-Hz-cppH)Cr(C0)3 (24) with ($-cppH)Cr(CO), (2), it appears superficially (see Figure 10) that the two are rather similar. However, a view along an orthogonal direction (Figure 11) reveals that in the
2.225(6) 2.255(5) 1.823(5) 1.355(12) 1.389(8)
Y 2034( 1) 2991(4) 2628(5) 2696(4) 3157(3) 3420(4) 3898(4) 4276(5) 4623(9) 4588(8) 4225(4) 4020(6) 3934(4) 3437(3) 3916(3) 3500(3) 879(3) 1733(3) 1608(3) 150(3) 1589(3) 1333( 2)
Cr-C(2) Cr-C(9A) Cr-C(22) C(l)-C(BA) C(3A)-C(4)
2.179(8) 2.244(5) 1.831(6) 1.402(8) 1.519(8)
2.238(6) 2.200(4) 1.823(5) 1.410(11) 1.401(6) 1.396(10) 1.385(17) 1.522(14) 1.414(7) 1.151(6)
dihydro complex 24 there has been a slippage of one molecule relative to its nearest neighbor. The net result of hydrogenating the C(8)=C(9) bond is not only an increase in the interplane distance from 3.45A in 2 to 3.6 8, in 24 but also in the volume of the unit cell by 5.5% relative to that of 2. The corresponding interplanar separations in (q5-cpp)Mn(C0)3 (15) and in [(s6-cppH)Fe(+C~Hs)]+PF6-are 3.40and 3.35 A, respectively. Extended Hiickel Molecular Orbital Studies. We turn now to the question of the trajectory taken by the ML, moieties as they migrate from the six- to the five-membered ring. As noted previously,' the orientations of tripodal fragments (such as Mn(C0)s or Cr(CO),) relative to the hydrocarbon play an important
1282 J. Am. Chem. SOC.,Vol. 115, No. 16, 1993
Decken et al. analogous migrations in the fluorenyl case. In both cases, the $-isomer is the favored structure; (~+-fluorenyl)FeCpisstabilized by 10.5 kcal mol-' and (75-cpp)FeCp by 13.4 kcal mol-'. The enhanced ease of migration in cpp complexes relative to the Hz-cpp or fluorenyl systems can be explained either on the basis of these molecular orbital calculations or, more straightforwardly, by using the simple bonding pictures 25-28. It is only
ML
2
24 25
Figure 10. View of two nearest neighbors in the unit cells of ($-cppH)Cr(CO):, (2) and of (H2-q6-cppH)Cr(CO)3(24).
26
ML
ML, 27
2 24 Figure 11. View of the packing of 2 and of 24 orthogonalto that in Figure 10, showing how the molecules of 24 are slipped relative to each other.
H
H
Figure 12. Possible pathways for haptotropic migrations in (cpp)Fe-
(CP). role in maximizing orbital overlap. This problem is greatly alleviated by allowing an Fe(CsH5) unit to move over the surface of the polycyclic ligand; use of a fixed orientation of the cyclopentadienyl ring is justifiable in terms of its very low barrier to rotation. In all cases, EHMO calculations were carried out for (CsHs)Fe migrations over fluorenide or cpp- surfaces with a constant CpFe-ligand distance of 1.59 A. The center of the six-membered ring was selected as the origin for all metal migrations, and this structure represents the arbitrary zero relative to which all other calculated energies are reported. In accord with the calculations of Albright, Hoffmann, and their co-workers on indenyl and fluorenyl complexes,' we find that there will be an unacceptably high barrier to the least-motion pathway (route A) of an Fe(C5Hs) unit directly across theC(3a)C ( 11) bond in the cpp system. As shown in Figure 12, the transit through the central six-membered ring (route B)provides a lower activation energy pathway, but the favored route (C) proceeds via an exocyclic ?r-allylic structure. The calculated barriers for these three migration pathways are 50.3, 39.3, and 32.5 kcal mol-', respectively. These compare with our EHMO-derived values of 56.0, 39.3, and 36.8 kcal mol-', respectively, for the
28
in the cpp complexes, if the migration proceeds via the exocyclic ?r-allylic transition state 27, that one can maintain the 1 0 ~ (naphthalene-like) aromatic character of two rings throughout the course of the reaction. This proposal gains support from the observation that the migration of an Mn(C0)3 group upon deprotonation of the cppH complex 13 is very facile, whereas the corresponding reactions using the dihydro-cppH complex 17 are rather slow; moreover, the intermediate (Hz-cpp)Mn(CO)3 (18) can be isolated. Since we can detect the intermediates 14 and 18, detailed kinetic studies are currently in progress with the goal of obtaining activation energies for these haptotropic shifts. These data will allow us to establish unambiguously whether the transformations 14- 15 (fast) and 18- 19 (slow) are genuinely kinetically controlled. Concluding Remarks. It would be of considerable interest to synthesize and characterize a genuinely trihapto-cpp complex to see whether the organometallic fragment can be trapped at the exocyclic binding site, as in 27, and experiments aimed at accomplishing this goal are currently being undertaken. We note that several $-benzylic systems in which the metal binds in an exocyclic fashion have been r e p ~ r t e d These . ~ ~ ~examples ~~ include the cases where the ML, units were either ( C S H ~ ) M ( C O(M )~ = Mo, W) (29, 30) or (acac)M ( M = Pd, Pt) (31, 32). The syntheses and rearrangement behavior of cpp complexes containing these ML, fragments will be thesubject of a future report.
M
M
29 : M = Mo(CO),(C,H,)
31 : M = Pd(acac)
30 : M = W(CO),(C,H,)
32 : M = Pt(acac)
Finally, as we recall that the cpp ligand represents one quarter of the C60 skeleton, it is interesting to speculate whether it may be possible to bind an ML, tripod to buckminsterfullerene in an (24) (a) King, R. B.;Fronzaglia, A. J . Am. Chem. SOC.1966,88,709. (b) Cotton, F. A.; Marks, T.J. J. Am. Chem. Soc. 1969, 91, 1339. (25) (a) Soncda, A.; Mann, B. E.; Maitlis, P. M.J . Chem. SOC.,Chem. Commun. 1975,108. (b) Roberts, J. S.;Klabunde, K.J. J . Am. Chem. SOC. 1977,99,2509. (c) Crascall, L.E.; Litster, S.A.; Redhouse, A. D.; Spencer.
J. L. J . Organomet. Chem. 1990, 394, C35 and references therein.
Haptotropic Shifts in Metal-Cyclopenta[deflphenanthrene 75- or $-manner. T h u s far, the crystallographically characterized complexes of e 6 0 in which metals are bonded to t h e outside of the cage are ones in which the fullerene functions as a polyalkene.26 In fact, t h e frontier orbitals of e 6 0 are 5-fold degenerate sets which are disposed in an essentially equatorial manner over t h e surface.27 T h e orbitals which are more localized on individual six- or five-membered rings and which a r e potential donors to ML3 fragments are energetically rather inaccessible. Nevertheless, when molecules of t h e type (fullerene)ML3 become available, they may exhibit spectacular fluxional behavior.
J. Am. Chem.SOC., Vol. 115, No. 16, 1993 1283
125.6 (C-8), 124.6 (C-7), 124.4 (C-5), 93.8 (C-2), 91.1 (C-3), 88.9 (C-1) (aromatic Cs);141.9, 129.1, 128.2, 123.3, 114.0, 102.1 (ring junction Cs); 36.5 (C-4). Mass spectrum (FAB +) m / z (relative intensity): 326 (86) (M)+, 270 (100) (M - 2CO)+, 242 (57) (M - 3CO)+, 190 (58) (CI~HIO)+. Anal. Calcd for Cl8HloCrO3: C,66.12; H, 3.30. Found: C, 65.87; H, 3.21. Deprotonation of (~6-4RCyclopenta[defIphenanthrene)Cr(CO)3 (2). In an NMR tube, an excess of solid NaH was treated with a solution of ( ~ ~ - c p p H ) C r ( Cin 0 )THF-ds ~ at room temperature. The mixture was cooled to-30 OC immediately after completion of the reaction. IH NMR (500 MHz, THF-d8,-30 OC): 6 7.68 (m, 2H), 7.53 ( d , J = 6.7 Hz, 2H), 7.26 (m, 2H), 7.15 (m, 2H), 5.40 (s, 1H). 13CNMR (125 MHz, THFExperimental Section ds.-3O0C): 6245.8 (Cr-CO); 126.1,125.1,122.5,113.0(aromaticCs); 134.1, 109.7, 101.4 (ring junction Cs);60.4 (C-4). All preparations were carried out under an atmosphereof dry nitrogen, [(q6-4~-Cyc~openta[deflphenanthreae)Mn(~~)~]+~~~(13). BrMnand solventswere dried according to standard procedures.28NMR spectra (C0)s (280 mg, 1 mmol), cppH (190 mg, 1 mmol), and AlCl3 (250 mg, were recorded on Bruker AM-500 or AC-200 spectrometers by using a 1.9 mmol) were heated under reflux in n-hexane (50 mL, dried over NaH 5-mm dual frequency IH-l3C probe and are reported relative to for 3 days, and freshly distilled prior to use) for 5 h. Upon the solution tetramethylsilane. Typical proton spectra wereobtained at 500.135 MHz cooling, water (7.5 mL) and toluene (7.5 mL) were added, and the in 8 scans in 32K data points over a 5-kHz spectral width or at 200.133 precipitate was removed on a sintered funnel. The aqueous layer was MHz in 8 scans in 16Kdata points over a 2-kHz spectral width. Carbon added dropwise to NH4PF6 (1.6 g, 9.8 mmol) in 5 mL of water. The spectra were obtained at 125.76 MHz in 16K data points over a 30-kHz organiclayerwasextractedwithwater (25mL),and thecombinedaqueous spectral width or at 50.32 MHz in 16Kdata points over a 15-kHz spectral layers were added to the NH4PF6 solution. The precipitate was filtered width. Proton-carbon shift-correlated spectra were recorded by using on a sintered funnel, washed with water, and dried in vacuo to yield the the 5-mm dual frequency lH-I3C inverseprobe. Fast atom bombardment product 13 as a yellow powder (290 mg, 0.61 mmol, 61%), mp 137 OC. (FAB) mass spectra were performed on a VG analytical micromass ZAB* HNMR (200 MHz, acetone-&): 6 8.48 (d, J = 9.1 Hz, lH), 8.2-8.0 ZE spectrometer with an accelerating power of 8 kV and a resolving (m, 3H), 7.71 (d, J = 6.9 Hz, lH), 7.51 (d, J = 6.9 Hz, lH), 7.26 (d, power of 10 000 and a VG11/250 data system. 3-Nitrobenzyl alcohol J = 6.2 Hz, lH), 6.86 (t, J = 6.5 Hz, lH), 5.09 (d, J = 22.9 Hz, lH), was used as the sample matrix and helium as the bombarding gas. 4.96 (d, J = 22.9 Hz, 1H). I3C NMR (50 MHz acetone-&,): 6 137.0, Microanalytical data are from Guelph Chemical Laboratories, Guelph, 134.0, 126.7, 126.3,97.0,95.7,95.2 (aromatic Cs); 143.0, 139.2, 124.9, Ontario. 127.1, 119.1, 118.0 (ring junction Cs); 39.2 (C-4). Mass spectrum The numbering scheme for cppH and metal complexesis shown below: )~)+, (FAB+) m / z (relative intensity): 329 (100) ( ( C I J H ~ ~ ) M ~ ( C O245 (9) ((ClsHlo)Mn)+, 190 (9.5) (CISHIO)+. 9 8 (~-4H-Cyclopenta[de~pheaanthrenyl)Mn(CO)~ (15). (a) By Depro1 9 a 7 - G 7 tonation of 13. ($-cppH)Mn(CO)3PF6 (0.35 g, 0.75 mmol) and 1,8bis(dimethy1amino)naphthalene (0.16 g, 0.75 mmol) were dissolved in 15 mL of CH2C12. The color of the reaction mixture changed from yellow to red immediately; stirring was continued for 3 h. The solvent volume was reduced to 5 mL, 15 mL of n-hexane was added, and the precipitate was filtered using Schlenk techniques. The solvent was removed under high vacuum, and the crude product was purified via flash chromatographyon silica using ether/hexanes 1:9 to yield a red solid, mp 4RCyclopenta[deflphenanthrene (cppH, 1) was obtained from Aldrich 77 OC. IH NMR (200 MHz, acetone-&): 6 7.87 (s, 2H, H-8,9), 7.77 Chemical Company and was used without further purification. IH NMR (d, J = 8.0 HZ of d, J = 1.2 Hz, 2H, H-3,5), 7.68 (d, J = 7.9 HZ of d, (200 MHz, acetone-d6): 6 7.87 (s, 2H, H-8,9), 7.85 (d, J = 7.9 Hz of J = 8.0 Hz, 2H, H-2,6), 7.61 (d, J = 7.9 H Zof d, J = 1.2 Hz, 2H, H-1,7), d , J = 0 . 5 H ~ , 2 H , H - 1 , 7 ) , 7 . 7 2 ( d , J = 7 . 1H Z O ~ ~ , J = O . ~ H Z , ~ H , (s, lH, H-4). H-1,7 attributions were made on the basis of their 5.88 H-3,5), 7.65 (d, J = 7.9 H Z of d, J = 7.1 Hz, 2H, H-2,6), 4.35 (s, 2H, NOE interactions with H-8,9 at 7.87 ppm. I3C N M R (125 MHz, H-4). The H-3,5 attributions were made on the basis of their NOE acetone-&): 6 130.8 (C-2,6), 129.0 (C-8,9), 124.2 (C-3,5), 120.0 (Cinteractions with the H-4 protons at 4.35 ppm. 13C NMR (50 MHz, 1,7) (aromatic Cs); 133.9, 104.9, 98.2 (ring junction Cs);58.2 ((2-4). acetone-&): 6 142.7 (C-8a,9a), 139.0 (C-3a,5a), 128.9 (C-10,l l), 128.0 Mass spectrum (FAB +) m/z (relative intensity): 328 (27) (M)+, 300 (C-2,6), 125.9 (C-8,9), 121.9 (C-3,5), 123.4 (C-1,7), 37.8 (C-4). The (21) (M-CO)', 272 (58) (M-2CO)+, 244 (26) (M - 3CO)+, 189 (100) C-3a.5a and C-8a,9a carbons were assigned on the basis of a I H - W (ClsHg)+. Anal. Calcd for ClsH9Mn03: C, 65.75; H, 2.95. Found: coupled experiment with the delays adjusted for long-range couplings. C, 65.26; H, 2.67. (q6-4RCyclopenta[defphenanthrene)Cr(CO)3 (2). CppH (1 g, 5.25 (b) From BrMn(C0)s. CppH (190 mg, 1 mmol) and NaH (24 mg, mmol) and Cr(C0)6 (1.15 g, 5.25 mmol) were heated under reflux in 1 mmol) were heated to reflux in 5 mL of THF for 10 h. The dark red 1,2-dimethoxyethane (70 mL) for 30 h. After unreacted Cr(C0)6 was mixture was filtered into a solution of BrMn(C0)s (274 mg, 1 mmol) separated by filtration, the solvent was removed on a rotary evaporator. in 10 mL of THF, and the reaction mixture was heated under reflux for Unreacted cppH was recovered by flash chromatography on silica using 12 h. The precipitate was filtered off, and the solvent was removed under hexane as eluent; upon changing the solvent to 1:1 hexane/CHzC12,2 was reduced pressure. The crude product was purified via flash chromaeluted and yielded an orange-red solid (340 mg, 1.04 mmol, 20%), mp tography on silica using hexanes/ether 9:l and yielded a red solid (132 193 OC dec. 'H NMR (500 MHz, 9:l acetone-dg/benzene-d6): 6 7.79 mg, 0.40 mmol, 40%). Spectral data were identical to those reported (d, J = 9.1 Hz, l H , H-8), 7.76 (d, J 7.2 Hz, l H , H-7), 7.73 (d, J = above. 7.2 Hz, l H , H-5), 7.67 (t, J = 7.2 Hz, l H , H-6, 7.62 (d, J = 9.1 Hz, (q6-cpp)Mn(CO)3 (14). In an NMR tube, an excess of solid 1,8lH,H-9),6.22 ( d , J = 6 . 5 Hz, l H , H - l ) , 6 . 1 4 ( d , J = 6.0Hz, 1H,H-3), bis(dimethy1amino)naphthalene was treated with a solution of (865.64 (t, J = 6.3 Hz, l H , H-2), 4.52 (s, 2H, H-4) (Using benzene-&, the cppH)Mn(CO),PF6 in CDzC12 at 4 0 " C . The solution turned red AB-system can be resolved: 6 3.98 (d, J = 20.0 Hz, lH, H-4,"dO), 3.56 immediately. IH NMR (500 MHz, CD2CI2,-25 " C ) : 6 8.21 (d, 9.0 Hz, (d, J = 20.0 H z , l H , H-4ex0)). I3C N M R ( 5 0 M H z , 9:l lH), 7.01 (d, J = 7.5 Hz, lH), 7.91 (t, J = 7.5 Hz, lH), 7.84 (d, J = acetone-&/benzene-&): 6 234.5 (Cr-CO); 130.4 (C-6), 129.8 (C-9), 9.0 Hz, lH), 7.80 (d, J = 7.5 Hz), 6.22 (s, H-4), 6.06 (d, J = 7.1 Hz, (26) (a) Hawkins, J. M. Acc. Chem. Res. 1992, 25, 150. (b) Fagan, P. lH), 5.78 (d, J = 5.7 Hz, lH), 5.64 (d, J = 7.1 Hz of d, J = 5.7 Hz, J.; Calabrese, J. C.; Malone, B. Acc. Chem. Res. 1992, 25, 134. (c) Balch, 1H). "C NMR (125 MHz, CD2CI2, -40 " C ) : 6 222.1, 134.2, 128.7, A. L.; Lee, J. W.;Noll, B. C.; Olmstead,M. M. J.Am. Cfiem.SOC.1992.114. 122.6, 120.5, 118.2, 95.4, 90.8, 77.1, 66.6. 10984 and references therein. (r16-4H-Cyclopenta[defjphenanthrene)Fe(C~5)PF6 (9). By analogy (27) Haddon, R. C. Ace. Chem. Res. 1992, 25, 127. to the general procedure of Helling and Hendrickson,3O cppH (0.95 g, (28) Perrin, D. D.; Perrin, D. R. Purification of Laboratory Chemicals; Pergamon Press: New York, NY, 1980. (29) Stout, G . H.; Jensen, L. H. X-ray Structure Determination, 2nd ed.; (30) Helling, J. F.; Hendrickson, W. A. J . Organomet. Chem. 1977, 141, John Wiley and Sons, Inc.: New York, 1989; p 76. 99.
1284 J. Am. Chem. SOC.,Vol. 115, No. 16, 1993 5 mmol), Cp2Fe (0.94 g, 5 mmol), aluminum powder (0.135 g, 5 mmol), and AIC13 (1.335 g, 10 mmol) were heated in 10 mL of decalin at 140 OC for 4 h. The mixture was cooled to 0 OC, 25 mL of water was added, and the inorganic solids were removed on a sintered funnel. The aqueous layer was isolated and extracted with ether (2 X 25 mL) and then treated with N H I P F ~(2 g, 12.5 mmol) in 5 mL of water. The precipitate was collected on a sintered funnel and dried under high vacuum to yield a brown solid (0.52 g, 1.44 mmol, 23% based on cppH), decomposing at 143 OC. 'H NMR (200 MHz, CD2C12): 6 8.09 (d, J 9.2 Hz, lH), 7.92 (m, ZH), 7.88 (d, J = 6.2 Hz, lH), 7.79 (d, J = 9.2 Hz, lH), 6.93 (d, J = 5.7 Hz, l H ) , 6.8 1 (d, J = 5.7 Hz, lH), 6.19 (t, J = 5.7 Hz, lH), 5.12 (d, J = 21.9 Hz, lH), 4.69 (d, J = 21.9 Hz, lH), 4.29 (s, 5H). 13C NMR (50 MHz, acetone-&): 6 133.5, 131.8, 125.7, 93.3, 85.1, 84.1, 82.6, 77.8 (aromatic Cs); 142.8, 137.8, 129.8, 126.1, 105.9, 100.4 (ring junction Cs); 39.4 ((2-4). Mass spectrum (FAB+) m / z (relative intensity): 31 1 (100) ((ClsHlo)FeCp)+, 189 (14) (C15H9)+. Anal.Calcd for C20H15F6FeP: C, 52.66; H, 3.32. Found: C, 52.77; H, 3.16. Traces of a second product were identified as (rrans-86,.r16-4H-Cyclopenta[deflphenanthrene)(Fe(C,Hs))2(PF&. IH NMR (200 MHz, acetone-d6): 6 7.49 (d, 6.0 Hz, 2H), 6.89 (d, 6.0 Hz, 2H), 6.30 (t, 6.0 Hz, ZH), 5.62 (s, ZH), 4.84 (s, 10H). 8,9-Dihydro-4H-cyclopen~deflphenanthrene (Hz-cppH) (16). Ethyl acetate (50mL) and 30 mgof Pd/C 5% were stirred at room temperature. H2 gas was admitted, and the apparatus was flushed with Hz three times. After 1 h was allowed for saturation of the catalyst, cppH (190 mg, 1 mmol) was added, and the reaction mixture was stirred for 3 days. The catalyst was filtered off using Celite, and the solvent was evaporated under reduced pressure to yield a white powder (190 mg, 0.99 mmol, 99%). IH NMR (200 MHz, acetone-&): 6 7.31 (d, J = 7.2 Hz, 2H), 7.16 (t, J = 7.3 Hz, ZH), 7.07 (d, J = 7.2 Hz, 2H), 3.82 (s, ZH), 3.07 (s,4H). 13CNMR(50MHz,acetone-d6):6 128.1,125.4,123.5 (aromatic Cs); 141.2, 139.9, 131.1 (ring junction Cs); 37.7 (C-4), 26.7 (C-8,9). [( ~ P - % ~ - D ~ ~ Y ~ ~ ~ o - ~ H - c Y c (17). ~ ~ & By analogy to 13, reaction of H2-cppH (190 mg, 1 mmol), BrMn(C0)s (275 mg, 1 mmol), and AlCl3 (250 mg, 1.9 mmol) yielded a pale yellow powder (404 mg, 0.85 mmol, 85%), mp 168 'C dec. 'H NMR (200 MHz, acetone-&): 6 7.59 (m, ZH), 7.40 (t, lH), 7.20 (d, J = 6.4 Hz, lH), 6.75 (d, J = 6.4 Hz, lH), 6.66 (t, 6.4 Hz, lH), 4.62 (d, J = 22.9 Hz, lH), 4.43 (d, J = 22.9 Hz, lH), 3.43 (m, ZH), 3.34 (m, 2H). I3C NMR (50 MHz, acetone-&): 6 217.1 (Cr-CO); 134.2, 127.1, 124.9, 100.4, 98.7, 98.0 (aromatic Cs); 143.1, 120.6, 115.6, 113.2, 97.1 (ring junction Cs); 38.7 ((2-4); 25.3, 25.0 (C-8,9). Mass spectrum (FAB+) m / z (relative intensity): 331 (100) ((C15H12)Mn(CO)3)+,247 (14) ((ClsH12)Mn + H)+, 191 (8) ClsHl~+.Anal. Calcd for C18H12F6MnO3P: C, 45.40; H, 2.54. Found: C, 45.65; H, 2.69. (q6-8,9-Dihydro-4Bcyclopenta[deflphenanthrene)Mn(CO)~ (18). By analogy to the preparation of 15, reaction of (H2-cppH)Mn(CO)3PF6 (200 mg, 0.42 mmol) and 1,8-bis(dimethylamino)naphthalene (90 mg, 0.42 mmol) afforded a dark red solid (71 mg, 0.21 mmol, 50%). IH NMR (200 MHz, acetone-d6): 6 7.64 (d, J = 8.2 Hz of d, J = 7.1 Hz, lH), 7.62 (d, J = 8.2 Hz, lH), 7.10 (d, J = 7.0 Hz, lH), 6.35 (t, J = 7.8 Hz, lH), 5.99 (s, l H ) , 5.88 (d, J = 5.8 Hz ofd, J = 7.8 Hz, l H ) , 5.55 (d, J = 5.8 Hz, lH), 3.39 (m, 4H). I3C NMR (50 MHz, acetone&): 6 222.7 (Cr-CO); 129.2, 119.3, 117.8, 96.0, 93.3, 84.0 (aromatic Cs); 144.8, 131.9, 130.2, 127.6, 116.3, 89.5 (ringjunctioncs); 71.1 (C4); 27.7, 26.3 (CHI Cs). Mass spectrum (FAB+) m/z (relative intensity): 660(8) (2M)+,576(10) (2M-3CO)+,331(100)(M+H)+, 274 (38) (M - 2CO)+, 247 (42) (M - 3CO)+, 191 (80) (CI~HII)'. (q5-8,9-Dihydro-4BCyclopenta[deflphenanthrenyl)Mn(CO)~ ( 19). Isomerization of 18 to 19 did not occur in solution (acetone) at ambient temperature within 72 h. (~6-Hz-cppH)Mn(CO)~ was heated to reflux in n-hexane for 1 h. The solvent was removed under reduced pressure, and the orange solid was dried under high vacuum, mp 79 OC. IH NMR (200 MHz, acetone-d6): 6 7.38 (d, J = 8.6 Hz, 2H, H-3,5), 7.27 (d, J 8.6 Hzof d , J = 6.7 Hz, 2H, H-2,6), 7.03 (d, J = 6.7 Hz, 2H, H-1,7), 5.66 (s, IH, H-4), 3.6-3.4 (m, ZH), 3.4-3.2 (m, 2H). I3C NMR (50 MHz,acetone-ds): 6 130.8(C-2,6), 122.6(C-3,5), 121.3(C-1,7) (aromatic Cs); 137.1,105.3,97.2 (ringjunction Cs); 58.3 (C-4), 26.7 (C-8,9). Mass (31) Sheldrick,G.M.SHELXTLPC, Release4,l;SiemensCrystaUographic Research Systems: Madison, WI 53719, USA,1990.
Decken et al. spectrum (FAB+) m/z (relative intensity): 660 (2) (2M)+, 576 (15 (2M - 3CO)+, 331 (80) (M)', 274 (34) (M - 2CO)+, 247 (75) (M H 3CO)+, 191 (100) (ClsH~l)+. (q6-8,9-Dihydro-4iY-cyclopent4deflphenanthrene)Cr(CO)~ (24). By analogy to the preparation of 2, H2-cppH (310 mg, 1.6 mmol) and Cr(CO)6 (540 mg, 2.45 mmol) were heated under reflux in 7 mL of nBu20 and 3 mL of T H F for 3.5 days. Unreacted Cr(C0)6 was filtered using Schlenk techniques, and the solvent was evaporated. The pure product was obtained via flash chromatography using CHzClz:hexanes, 2: 1 to yield a yellow solid (246 mg, 0.75 mmol, 47%), mp 148 OC. IH NMR (200MHz,acetone-&): 67.31 ( d , J = 7 . 2 H z , 1H),7.23(t,J=7.2Hz,
+
lH),7.12(d,J=7.1Hz,lH),5.99(d,J=6.1Hz,lH),5.57(t;J= 6.2 Hz, lH), 5.49 (d, J = 6.2 Hz, lH), 4.13 (d, J = 21.4 Hz, lH), 3.92 (d, J = 21.4 Hz, lH), 3.1-3.0 (m, 4H). I3C NMR (50 MHz, acetone&): 6 235.3 (Cr-CO); 130.1, 126.0, 123.7, 94.3, 90.7 (2C) (aromatic Cs); 140.5, 136.7, 131.4, 114.6, 108.4, 107.2 (ring junction Cs); 38.0 (C-4); 25.7, 25.6 (C-8,9). Mass spectrum (DEI+) m / z (relative intensity): 328 (25) (M)+, 272 (27) (M-ZCO)+, 244 (100) (M-3CO)+, 189 (8) (CisHd+. X-ray Crystal Structure Determinations for 2, 24, and 15. Crystal data and refinement parameters are collected in Table I, and atomic coordinates and bond lengths are listed in Tables 11-VI. All crystals were grown by vapor diffusion techniques29using 1,2-dichloroethane and n-heptane at -22 OC. The crystals were mounted on fine glass fibres with epoxy cement. The unit cells were determined by automatic indexing of 25 centered reflections. Intensity data for 2 and 24 were collected on a Siemens P4 diffractometer fitted with a rotating anode using graphitemonochromated Mo Ka X-radiation (A = 0.71073 A) at room temperature. Data collection for 15 was performedon a Siemens R3m/V diffractometer using graphite-monochromated Ag Ka (A = 0.560 86 A). Three check reflections were measured every 97 reflections. The heavy atom positions were obtained using Patterson methods, and phase extension and ~ ~Fourier ) ~ (difference C O ) techniques ~ ~ P Frevealed ~ - the remaining non-hydrogen atoms. Hydrogen atoms for 2 and 24 were included in calculated positions (d(C-H) = 0.96 A) and refined using a riding model and common isotropic temperature factors. Hydrogen atom positions for 15 were determined by difference Fourier analysis and refined isotropically using individual Us. Thermal motion of the ligand in 24 was corrected employing librational rigid-body motion analy~is.'~Scattering factors were supplied by the software. Data reduction, structure solution, refinement, graphics, and table generation programs are contained in the SHELXTL program library.31 Molecular Orbital Calculationswere performedvia the extended Hiickel method using weighted Hij orbital drawings were obtained by use of the program CACAO.34 The geometry of the polycyclic ligand was an idealized, planar version taken from the X-ray crystal structure of ($-cpp)Mn(CO)3. The following distances were used: Fe-Cp = 1.66 A and Fe-cpp = 1.59 A. Orbital parameters were taken from ref 1. Acknowledgment. We thank the Natural Sciences and Engineering Council of Canada for financial support. A.D. is the recipient of a McMaster University Centennial Scholarship and is an Ontario Graduate Scholar. Mass spectra were obtained courtesy of Dr. Richard Smith of the McMaster Regional Centre for Mass Spectrometry. We thank Dr. Don Hughes and Brian Sayer for advice on 2D N M R techniques. Finally we thank Dr. Carlo Mealli, CNR, Florence, Italy for providing CACAO Version 2.2. Supplementary Material Available: Tables listing bond angles and displacement coefficientsfor 2,24, and 15 (8 pages); observed and calculated structure factors (22 pages). Ordering information is given on any current masthead page.
(32) Schomaker, V.; Trueblood K. N. Acta Crystallogr. 1968, E24, 63. (33) (a) Hoffmann, R.J. Chem. Phys. 1963,39,1397. (b) Hoffmann, R.; Lipscomb, W. N. J. Chem. Phys. 1962,36,2179,3489. (c) Ammeter, J. H.; Biirgi, H.-B.; Thibeault, J. C.; Hoffmann, R.J. Am. Chem. Soc. 1978,100, 3686. (34) Mealli, C.; Proserpio, D. M. J. Chem. Educ. 1990, 67, 3399.
